Tap and Drill Bit Selection Guide - Bosch Power Tools

Tap and Drill Bit Selection Guide
American Standard and Unified Form Threads Tap
drill size is approximately 75% of threaded depth.
Thread Nominal Size Standard Drill Size Decimal
0–80 NF 3/64" .0469"
1–64 NC 53 .0595"
1–72 NF 53 .0595"
2–56 NC 50 .0700"
2–64 NF 50 .0700"
3–48 NC 47 .0785"
3–56 NF 45 .0820"
4–40 NC–UNC 43 .0890"
4–48 NF 42 .0935"
5–40 NC 38 .1015"
5–44 NF 37 .1040"
6–32 NC–UNC 36 .1065"
6–40 NF 33 .1130"
8–32 NC–UNC 29 .1360"
8–36 NF 29 .1360"
10–24 NC–UNC 25 .1495"
10–32 NF–UNF 21 .1590"
3/16–24 NS 26 .1470"
3/16–32 NS 22 .1570"
12–24 NC 16 .1770"
12–28 NF 14 .1820"
14–20 NS 10 .1935"
1/4–20 NC–UNC 7 .2010"
1/4–28 NF–UNF 3 .2130"
5/16–18 NC–UNC F .2570"
5/16–24 NF–UNF I .2720"
3/8–16 NC–UNC 5/16" .3125"
3/8–24 NF–UNF Q .3320"
7/16–14 NC–UNC U .3680"
7/16–20 NF–UNF 25/64" .3906"
1/2–13 NC–UNC 27/64" .4219"
1/2–20 NF–UNF 29/64" .4531"
9/16–12 NC–UNC 31/64" .4844"
9/16–18 NF–UNF 33/64" .5156"
5/8–11 NC–UNC 17/32" .5312"
5/8–18 NF–UNF 37/64" .5781"
3/4–10 NC–UNC 21/32" .6562"
3/4–16 NF–UNF 11/16" .6875"
7/8–9 NC–UNC 49/64" .7656"
7/8–14 NF–UNF 13/16" .8125"
1–8 NC–UNC 7/8" .8750"
1–14 NS 15/16" .9375"
1-1/8–7 NC–UNC 63/64" .9844"
1-1/8–12 NF–UNF 1-3/64" 1.0469"
1-1/4–7 NCUNC 1-7/64" 1.1094"
1-1/4–12 NF–UNF 1-11/64" 1.1719"
1-3/8–6 NC–UNC 1-7/32" 1.2188"
1-3/8–12 NF–UNF 1-19/64" 1.2969"
1-1/2–6 NC–UNC 1-11/32" 1.3438"
1-1/2–12 NF–UNF 1-27/64" 1.4219"
1-3/4–5 NC–UNC 1-9/16" 1.5625"
2–4-1/2 NC–UNC 1-25/32" 1.7813"
2-1/4–4-1/2 NC-UNC 2-1/32" 2.0313"
2-1/2–4 NC–UNC 2-1/4" 2.2500"
2-3/4–4 NC–UNC 2-1/2" 2.5000"
3–4 NC–UNC 2-3/4" 2.7500"
3-1/4–4 NC–UNC 3" 3.0000"
3-1/4–4 NC–UNC 3-1/4" 3.2500"
3-3/4–4 NC–UNC 3-1/2" 3.5000"
4–4 NC–UNC 3-3/4" 3.7500"
Metric Threads
French International Standard (D.I.N.)
Tap Size Standard Drill Size Decimal
2.5–.45 French 5/64" .0781"
2.6–.45 D.I.N. #45 .0820"
3–.50 D.I.N. #40 .0980"
3–.60 French #39 .0995"
3–.75 Optional #43 .8090"
3.5–.60 French & D.I.N. #33 .1130"
4–.70 D.I.N. 1/8" .1250"
4–.75 French 1/8" .1250"
4.5–.75 French & D.I.N. #26 .1470"
5–.75 Optional #19 .1660"
5–.80 D.I.N. 11/64" .1719"
5–.90 French #20 .1610"
5–1.00 Optional 5/32" .1563"
5.5–.75 Optional 3/16" .1875"
5.5–.90 French & D.I.N. #14 .1820"
6–1.00 French & D.I.N. 13/64" .2031"
6–1.25 Optional 3/16" .1875"
7–1.00 French & D.I.N. 15/64" .2344"
7–1.25 Optional #1 .2280"
8–1.00 French J .2770"
8–1.25 D.I.N. 17/64" .2656"
9–1.00 French 5/16" .3125"
9–1.25 D.I.N. 5/16" .3125"
10–1.00 Optional 23/64" .3594"
10–1.25 Optional 11/32" .3437"
10–1.50 French & D.I.N. 11/32" .3437"
11–1.50 D.I.N. 3/8" .3750"
12–1.25 Optional 7/16" .4375"
12–1.50 French 13/32" .4063"
12–1.75 D.I.N. 27/64" .4219"
12–1.75 Optional 29/64" .4531"
13–1.50 Optional 29/64" .4531"
13–2.00 Optional 7/16" .4375"
14–1.25 Optional 33/64" .5156"
14–1.75 Optional 1/2" .5000"
14–2.00 French & D.I.N. 15/32" .4687"
15–1.75 Optional 17/32" .5313"
15–2.00 Optional 33/64" .5156"
16–1.50 Optional 37/64" .5781"
16–2.00 French & D.I.N. 35/64" .5469"
17–2.00 Optional 19/32" .5937"
18–1.50 Optional 21/32" .6563"
Taper Pipe — For tapping without reaming
Thread Drill Thread Drill Thread Drill
1/16" D 3/4" 59/64" 2-1/2" 2-5/8"
1/8" R 1" 1-5/32" 3" 3-1/4"
1/4" 7/16" 1-1/4" 1-1/2" 3-1/2" 3-3/34"
3/8" 37/64" 1-1/2" 1-47/64" 4" 4-1/4"
1/2" 45/64" 2" 2-7/32" – –
Straight Pipe
Thread Drill Thread Drill Thread Drill
1/16" 1/4" 1/2" 23/32" 1-1/2" 1-3/4"
1/8" 11/32" 3/4" 59/64" 2" 2-7/32"
1/4" 7/16" 1" 1-5/32" 2-1/2" 2-21/32"
3/8" 37/64" 1-1/4" 1-1/2" – –

f
f
f
f
f
Black Oxide Taps and Dies
Heat-treated
carbon steel
provides long
life and clean,
accurate threads
Rolled threads
provide more
accuracy than
machined threads
Black oxide
coating
provides
corrosion
resistance
Laser-etched
marking
ensures size
identification
won't wear off
Product Info — Tap Point Styles
Taper
Plug
Bottoming
Taper
f f8–10 chamfered threads at the
tip ideal for starting threads in
tough materials
f Longest chamfer of all
three types
f Commonly used in through holes
and with materials where a guide
is necessary
f Requires less torque due to
more working teeth
Plug (most widely used)
f fGeneral purpose tap, with
3–5 chamfered threads
f Used when there is sufficient
room on a blind hole and tapping
to the bottom is not required
Bottoming
f fUsed after the threads have
been started
f 1–3 chamfered threads at the tip
are enough to start the hole and
taps all the way to the bottom
Note: Tap and die size is indicated by two
numbers. The first number represents the
diameter of the screw or bolt. The second
number represents threads per inch. The
letters after the tap size indicate particular
screw or bolt standard:
NC = National Coarse
NF = National Fine
NS = National Special
NEF = National Extra Fine
NPT = National Pipe Taper
BSP = British Standard Pipe
D.I.N. = French International Standard
Example: A 1/4-20 NC tap will cut 1/4"
outside diameter with 20 threads per inch
for a National Coarse-type screw.